Figure 2. Spi/EGFR/MAPK signaling is induced in ISC tumors and the niche.

(a-d) Di-phosphorylated ERK (a’, c’; b, d, red) in midguts expressing GFP (a; b, green) or GFP and N^RNAi (c; d, green) with esg^ts for 2 days.

(e-f) β-galactosidase (e,f; e’,f’, red) in midguts of flies bearing vn-lacZ (vn^P1749) and expressing GFP (e’, green) or GFP and N^RNAi (f’, green) with esg^ts for 2 days.

(g) Mean normalized expression (NE) value (RPKM, log₂) from n=2 independent experiments of EGFR ligand (spi, Krn, vn) and signaling target (aos) mRNA determined by mRNA sequencing of midguts expressing GFP (control, red) or GFP and N^RNAi (blue) with esg^ts for 3 days. The adjusted fold change in gene expression in tumorous midguts (blue), normalized to control midguts (red), is indicated. The Benjamini-Hochberg adjusted p-value for spi is 7.71e-322; vn, p= 3.25e-66; aos, p= 2.84e-264.

(h) Mean normalized expression (NE) value (RPKM, log2) from n=2 independent experiments of EGFR ligand (spi, Krn and vn) and signaling target (aos) mRNA determined by mRNA sequencing of esg⁺ cells sorted from control midguts expressing GFP (red) or from tumorous midguts expressing GFP and N^RNAi (blue) with esg^ts for 3 days. The adjusted fold change in gene expression in sorted esg⁺ tumor cells (blue), normalized to esg⁺ cells from control midguts, is indicated. Benjamini-Hochberg corrected p-value for spi is 0.02924066; aos, 4.52e-05.

NS, not significant. DNA is in a’’ and c’’; e’ and f’ (blue). Scale bars in a-a’’, 35 μm; b, 10 μm; cc’’, 40 μm; d, 10 μm; e-e’, 35 μm and f-f’, 45 μm.